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%I #19 Mar 27 2021 01:22:34
%S 1,1,1,0,1,0,1,0,3,1,6,2,25,18,88
%N Number of well-connected free polyominoes with n cells, where a polyomino is defined as well-connected if, for all the squares it contains, the removal of that single square would result in an intact polyomino.
%C Examples of well-connected polyominoes are rectangles and loops:
%C .
%C XXXX
%C XXXX (rectangle)
%C .
%C XXX
%C X X (loop)
%C XXX
%H John Mason, <a href="/A341219/a341219.pdf">Well connected polyominoes</a>
%e a(4) = 1 because the 2 X 2 square polyomino is the only tetromino to be well-connected. The removal of any single square always results in an intact tromino. In each of the other 4 tetrominoes, there is a square whose removal would result in something that is not an intact polyomino.
%Y Cf. A000105.
%K nonn,more
%O 0,9
%A _John Mason_, Feb 07 2021
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